Resumen:

A spatial model of party competition is studied in which: (i) Parties
are supposed to have ideology. By this we mean that their goal is to maximize
the welfare of their constituencies. (ii) The policy implemented after the
election does not need to coincide wiA spatial model of party competition is studied in which: (i) Parties
are supposed to have ideology. By this we mean that their goal is to maximize
the welfare of their constituencies. (ii) The policy implemented after the
election does not need to coincide with the one proposed by the winner. The
policy implemented should be a compromise that considers the proposals
made by the di¤erent parties. In the case of proportional representation this
compromise is modeled as a convex combination of the proposed policies
with weights proportional to the number of votes obtained by each party. We
provide some existence theorems and compare the equilibrium in our model
with the equilibrium that exists under some probabilistic models. It is also
shown that proportional representation will create incentives for the parties to
announce radical platforms.[+][-]